etherscan api not returning contract bytecode for some contracts

Question

For some contracts, the Etherscan api returns empty bytecode (0x). For example for:

• 8AB399CBB9FDB9A36518A7E7EDDF89158E56C595 (even though the contract exists: https://etherscan.io/address/0x8AB399CBB9FDB9A36518A7E7EDDF89158E56C595 )
• A9131EC8390D9AE069A061A4898B8A35495C4259 (even though this contract also exists: https://etherscan.io/address/0xA9131EC8390D9AE069A061A4898B8A35495C4259 )

For some other contracts, the API functions properly:

• C1E088fC1323b20BCBee9bd1B9fC9546db5624C5 (https://etherscan.io/address/0xc1e088fc1323b20bcbee9bd1b9fc9546db5624c5#multichain-portfolio )

I need the deployed bytecode to implement my simulation of the EXTCODEHASH opcode.

Does the API not function properly?

The source code of my API call for clarity:

@classmethod
def _fetch_contract_source_code(cls, contract_address, api_key, api_base_url):
    params = {
        'module': 'proxy',
        'action': 'eth_getCode',
        'address': contract_address,
        'apikey': api_key
    }

    response = requests.get(api_base_url, params=params)

    if response.status_code != 200:
        raise Exception(f'Error fetching source code: {response.status_code} - {response.text}')

    data = response.json()

    if len(data['result']) < 3:
        return False

    return data['result'];